The present invention starts from a three-phase bridge rectifier system according to the definition of the species of the main claim. From German DE 42 25 359 C1, three-phase bridge rectifier systems are known having two semiconductor diodes per phase, in which the voltage-stabilizing properties of individual Zener-diodes are used. In this kind of voltage stabilization, however, when the rectifier system is to be designed for higher motor vehicle electrical system voltages, such as 42 volts, the manufacturing tolerance of the breakdown voltage of the Zener-diodes is too great to achieve a reliable voltage limitation at a given minimum ripple to be passed.
the three-phase bridge rectifier system, according to the present invention, having the characterizing features of the independent claim, on the other hand, has the advantage, compared to this, of being able to achieve reliable voltage stabilization even for high motor vehicle electrical system voltages, through the use of the bridge rectifier system itself, in particular, for example, a voltage limitation is reliably achieved in the case of an operating voltage at B+ of 42 volt and a maximum ripple at B+ of 47 volt, as soon as the voltage at B+ has reached a value of 55 volt.
As a result of the measures specified in the dependent claims, advantageous further refinements and improvements of the rectifier indicated in the main claim are possible.
The present invention relates to a three-phase bridge rectifier system.
German Patent No. 42 25 359 describes three-phase bridge rectifier systems having two semiconductor diodes per phase, in which the voltage-stabilizing properties of individual Zener-diodes are used. In this kind of voltage stabilization, however, when the rectifier system is to be designed for higher motor vehicle electrical system voltages, such as 42 volts, the manufacturing tolerance of the breakdown voltage of the Zener-diodes is too great to achieve a reliable voltage limitation at a given minimum ripple to be passed.
The three-phase bridge rectifier system, according to the present invention on the other hand, has the advantage, compared to this, of being able to achieve reliable voltage stabilization even for high motor vehicle electrical system voltages, through the use of the bridge rectifier system itself, in particular, for example, a voltage limitation is reliably achieved in the case of an operating voltage at B+ of 42 volt and a maximum ripple at B+ of 47 volt, as soon as the voltage at B+ has reached a value of 55 volt.
Especially by providing Zener-diode pairs does it become possible to produce high clamp voltages with narrow tolerance ranges.
It is also particularly advantageous to make available high clamp voltages by the integration of at least two p-n junctions in a single semiconductor element in the form of three-layer or four-layer diodes. In particular, the problem of the instability of the breakdown as a result of excessive warming because of the high load-dump current and the positive temperature response of the breakdown voltage is eliminated, since the voltage drops off, shortly after the breakdown, to a low value which is then only still required to leave the three-layer or four-layer element in the patched through condition.